*       }
 *     };
 * iteratorTester.test();
 * iteratorTester.testForEachRemaining();
 * }</pre>
 *
 * <p><b>Note</b>: It is necessary to use {@code IteratorTester.KnownOrder} as shown above, rather
 * than {@code KnownOrder} directly, because otherwise the code cannot be compiled.
 *
 * @author Kevin Bourrillion
 * @author Chris Povirk
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

 * for use in test code.
 *
 * <p><b>Do not use this interface</b> for public or protected declarations: it is a fig leaf for
 * bad design, and it does not prevent anyone from using the declaration---and experience has shown
 * that they will. If the method breaks the encapsulation of its class, then its internal
 * representation will be hard to change. Instead, use <a

import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

/**
 * File name filter that only accepts files matching a regular expression. This class is thread-safe
 * and immutable.
 *
 * @author Apple Chow
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public final class PatternFilenameFilter implements FilenameFilter {

  private final Pattern pattern;

  /**

    return this;
  }

  private long elapsedNanos() {
    return isRunning ? ticker.read() - startTick + elapsedNanos : elapsedNanos;
  }

  /**
   * Returns the current elapsed time shown on this stopwatch, expressed in the desired time unit,
   * with any fraction rounded down.
   *
   * <p><b>Note:</b> the overhead of measurement can be more than a microsecond, so it is generally

 *       }
 *     };
 * iteratorTester.test();
 * iteratorTester.testForEachRemaining();
 * }</pre>
 *
 * <p><b>Note</b>: It is necessary to use {@code IteratorTester.KnownOrder} as shown above, rather
 * than {@code KnownOrder} directly, because otherwise the code cannot be compiled.
 *
 * @author Kevin Bourrillion
 * @author Chris Povirk
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

    return this;
  }

  private long elapsedNanos() {
    return isRunning ? ticker.read() - startTick + elapsedNanos : elapsedNanos;
  }

  /**
   * Returns the current elapsed time shown on this stopwatch, expressed in the desired time unit,
   * with any fraction rounded down.
   *
   * <p>Note that the overhead of measurement can be more than a microsecond, so it is generally not

 * for use in test code.
 *
 * <p><b>Do not use this interface</b> for public or protected declarations: it is a fig leaf for
 * bad design, and it does not prevent anyone from using the declaration---and experience has shown
 * that they will. If the method breaks the encapsulation of its class, then its internal
 * representation will be hard to change. Instead, use <a

   * EndpointPair}s, we keep track of the nodes that we have visited. When processing endpoint
   * pairs, we skip if the "other node" is in the visited set, as shown below:
   *
   * <pre>
   * Nodes = {N1, N2, N3, N4}
   *    N2           __
   *   /  \         |  |
   * N1----N3      N4__|
   *
   * Visited Nodes = {}
   * EndpointPair [N1, N2] - return